There are many situations in which control of fluid flow is required. For example, it is often desirable to provide a predetermined quantity of a liquid sample e.g. for testing purposes, and difficulties can arise in achieving this accurately and reliably in an easy manner not requiring complex equipment and/or skilled operators, particularly where very small quantities of liquid are involved. This applies e.g. with sample testing devices having one or more capillary passages for testing for the presence or amount of a component of interest in a liquid sample, commonly a body fluid such as blood (whole blood or plasma), urine, saliva, etc.
In the prior art, flow of liquid sample though a device is typically controlled by a system using external motive force, for example syringes and bellows (see for example US2001/0003286). Such equipment requires the device to be complex, and as a result, more expensive and not suited to the Point of Care market.
The present inventions to overcome or ameliorate some or all of the problems associated with the prior art.